The proposed research examines the phenomenon of pluralistic ignorance: the tendency to infer that the identical actions or responses of the self and others reflect different internal states. The long-term objectives of the proposal are twofold: (1) to explore the consequences and manifestations of pluralistic ignorance and (2) to identify the mechanisms that underlie and sustain pluralistic ignorance. The guiding hypothesis is that pluralistic ignorance arises most commonly in contexts where individuals believe that fear of embarrassment, or some cognate trait, is a sufficient cause for their own behavior but not for the behavior of others. The proposal's objectives will be pursued through an interrelated program of experimental and correlational studies. Study 1 examines the role that pluralistic ignorance plays in group cohesion and group morale. Study 2 examines the impact that pluralistic ignorance has on individuals' interpretations of their social context. Studies 3 and 4 examine the role that pluralistic ignorance plays in people's responses to stressful life events. Additionally, Study 4 endeavors to demonstrate that an intervention designed to diminish pluralistic ignorance can facilitate successful coping with a stressful life event. Studies 5, 6, and 7 examine more directly the mechanisms underlying pluralistic ignorance, including the role of causal explanation and communication. Studies 8 and 9 pursue the possibility that pluralistic ignorance arises not only when people interpret the similar behavior of the self and others differently, but also when people fail to recognize the similarity of their public behavior to that of others. This program of research should help illuminate (a) the conditions under which people develop erroneous perceptions of deviance, (b) the relation of perceived deviance to psychological adjustment, and (c) the means by which the illusion of uniqueness can be prevented.